Clamp



Aug. 1, 1939. D. l FARMER CLAMP Filed July 19, 1937 INVENTOR. 5

ATTORNEYS Patented Aug. 1, 1939 PATENT OFFICE CLAMP Delbert L. Farmer,.Cincinnati, Ohio, assignor to The Cincinnati Tool Company, Norwood, Ohio,

a corporation of Ohio Application July 19, 1937, Serial No. 154,382

1 Claim.

This invention relates to improvements in clamps and is adaptable to that type of clamp which is known as a joiners clamp. This type of clamp employs a fixed, clamping jaw at one end of a bar and a second jaw slidable upon the bar and carrying a screw parallel to the bar adapted to cooperate with the stationary jaw.

The invention is particularly directed to a new and improved means for holding a sliding, clamp jaw in any adjusted position on the supporting bar as the clamping pressure is applied to the work placed between the jaws. It is, of course, obvious that the improvements can be applied to other types of clamps, for example, those in which the screw operates through a fixed jaw and in which the movable jaw directly engages the work. Broadly speaking, therefore, the improvements are directed to the means for holding a clamp jaw in fixed position with respect to the bar on which it slides.

It has been the object of the present inventor to provide an improved means having the function of automatically holding the jaw in fixed position when the pressure is applied against the work, which means becomes more effective as the pressure is increased.

It has been the further objective to provide a means of this character which is extremely simple,- easily assembled, inexpensive, and replaceable, and utilizes a strictly conventional element of a character such that it can be utilized in its conventional condition, that is, without change.

The present inventor has attained these objectives and, in the attainment, discovered that a conventional screw is admirably suited for this use when incorporated in the jaw between the jaw and the bar. The screw threads provide a multiplicity of closely spaced edges effectively biting into the bar to prevent efiiciently, any slippage of the jaw.

Other objects and certain advantages will be more fully apparent from a description of the accompanying drawing, in which:

Figure 1 is a side view of a clamp embodying the improvement.

Figure 2 is an enlarged, fragmentary view with the parts broken away to show in detail the improved jaw fixing means.

Figure 3 is a fragmentary sectional view taken on line 33, Figure 2.

Figure 4 is a view taken similarly to Figure l but showing the clamp in use, with the work clamped between the jaws thereof. 55 Figure 5 is a fragmentary, detailed view, showing the movable jaw in section and in position when clamping pressure has been applied.

As stated, the present improvement is entirely concerned with the improved means for holding the adjustable jaw in position. For this reason, 5 the remainder of the structure is immaterial, although it is shown for the purpose of illustrating an environment for the improvement.

Referring to the drawing, the bar of the clamp is illustrated at Ill, being of plain rectangular 10 shape in cross section. A jaw II is fixed at one end of the bar, the bar projecting into the rectangular bore H of the jaw, and being fixed therein by means of a pin I3. This jaw projects laterally well away from the bar and has a work engaging pad [4 at the outer end of its inner side edge. The movable jaw 15 is of the same shape as is the jaw ll. However, its contact pad I6 is adjustable. The work engaging pad I6 is axially aligned with the pad I4 and is mounted on the inner end of a screw 11 through the medium of a ball and socket joint I8. The screw l1 traverses the outer end of the jaw l5, parallel to the bar, and has a handle l9 at its outer end. j

This jaw l5 includes a rectangular bore which is of slightly greater width than the bar thickness to provide a sliding fit. Its other dimension, however, is greater than that of the bar in order to permit a slight cooking or canting of the bar when pressure is applied against the work, as in Figure 4.

The means concerned in the present improvement, as shown in detail, consists of a short, plain screw 20. The element 20 may be additionally referred to as a short section of screwthreaded rod which is preferably threaded entirely from one end to the other. A screwthreaded bore 2| is provided in the jaw. The axis of this bore is parallel to the axis of the clamping screw carried by the jaw and slightly overlapping the rectangular bore of the jaw so that the lower portion of the screw projects into the rectangular bore and engages against the bar.

When the screw is in place, the jaw is held fairly rigidly, directly at right angles to the bar; yet there is suflicient clearance to permit sliding movement along the bar unless the jaw is slightly cocked, which occurs when the work pressure is applied. When the jaw is thus in use, the threads of the screw bite into the metal of the bar, as shown in Figure 5, the contact or engagement being of increasing pressure toward the rearmost thread. In other words, the pressure inthe other, said adjustable jaw including a bore traversed by the bar, said jaw including a recess therein adjacent to said bore, a short section of screw threaded into said recess, the axis of said screw being generally parallel with the bar, and the threads of the screw providing a series of cross edges engaging the bar, said edges adapted to bite into the bar and grip the same when said jaw is canted.

DELBERT L. FARMER. 

